User blog comment:GalaxiaWild/Why are angels called demons in Devil May Cry 4?/@comment-1512913-20120731180230

Manga says that angels and demons were once the same thing, and I'm sure that there's also a mention of angels in DMC1 (somewhere) but I can't find it now.

Mundus kinda resembles a fallen angel, could work good with him being a reference to Lucifer.

My 2 cents, even though Nero said that Credo had become a demon + library files and shit, he wasn't evil and died as "holy light and golden dust" thus indicating a possibility that he became an ANGEL instead of demon.

Same goes for other Holy Knights of the Order.

Not to mention (in reverse, lol) in Bayonetta, angels under their golden armors look pretty much how you could imagine a demon.